Interfacial Charge Transfer and Effective Termination of Electron Recombination Process in (ZnO)(1-x)/2(Bi2O3)x(Dy2O3)(1-x)/2 Heterostructured Nanocomposite Material under Visible Light Irradiation

Abstract

We have synthesized a novel heterostructured composite material-(ZnO)(1-x)/2(Bi2O3)x(Dy2O3)(1-x)/2 wherein electron-hole recombination has been successfully inhibited by an interfacial charge-transfer mechanism across a semiconductor interface. As a result of this, the material possessed enhanced photoresponse under visible light irradiations. X-ray diffraction analysis shows the material to be highly nanocrystalline in nature. The band gap energy as calculated from the UV-vis-diffused reflectance spectroscopy spectrum was found to be 2.68 eV. Morphological studies by high-resolution scanning electron microscopy and high-resolution transmission electron microscopy analyses show the presence of distinct microrod-shaped αBi2O3 and spherical ball-like clusters of ZnO and Dy2O3 nanoparticles. X-ray photoelectron spectroscopy and energy-dispersive X-ray analyses confirm the presence of Bi, Zn, Dy, and O in the material. Atomic force microscopy (AFM) analysis revealed the high surface roughness and porosity of the prepared composite. Electron paramagnetic resonance analysis confirmed the in situ generation of OH•radicals under visible light irradiation. The photocatalytic efficiency of the (ZnO)(1-x)/2(Bi2O3)x(Dy2O3)(1-x)/2 composite material was evaluated by the photooxidation of Orange G (OG) dye molecules under visible light irradiation. The catalyst retained its original efficiency even after the 3rd cycle of its reuse thereby validating the economic feasibility of the system. By-product analysis by ESI-MS+ analysis proved the complete degradation of the OG molecules from the aqueous solution.